Nuclear Accumulation of Cytosolic Glyceraldehyde-3-Phosphate Dehydrogenase in Cadmium-Stressed Arabidopsis Roots    

Abstract

NAD-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a ubiquitous enzyme involved in the glycolytic pathway. It has been widely demonstrated that mammalian GAPDH, in addition to its role in glycolysis, fulfills alternative functions mainly linked to its susceptibility to oxidative posttranslational modifications. Here, we investigated the responses of Arabidopsis (Arabidopsis thaliana) cytosolic GAPDH isoenzymes GAPC1 and GAPC2 to cadmium-induced stress in seedlings roots. GAPC1 was more responsive to cadmium than GAPC2 at the transcriptional level. In vivo, cadmium treatments induced different concomitant effects, including (1) nitric oxide accumulation, (2) cytosolic oxidation (e.g. oxidation of the redox-sensitive Green fluorescent protein2 probe), (3) activation of the GAPC1 promoter, (4) GAPC1 protein accumulation in enzymatically inactive form, and (5) strong relocalization of GAPC1 to the nucleus. All these effects were detected in the same zone of the root tip. In vitro, GAPC1 was inactivated by either nitric oxide donors or hydrogen peroxide, but no inhibition was directly provided by cadmium. Interestingly, nuclear relocalization of GAPC1 under cadmium-induced oxidative stress was stimulated, rather than inhibited, by mutating into serine the catalytic cysteine of GAPC1 (C155S), excluding an essential role of GAPC1 nitrosylation in the mechanism of nuclear relocalization, as found in mammalian cells. Although the function of GAPC1 in the nucleus is unknown, our results suggest that glycolytic GAPC1, through its high sensitivity to the cellular redox state, may play a role in oxidative stress signaling or protection in plants.

Cytosolic Phosphorylating Glyceraldehyde-3-Phosphate Dehydrogenases Affect Arabidopsis Cellular Metabolism and Promote Seed Oil Accumulation

“…Both YFP-GAPC1 and YFP-GAPC2 were localized in the cytosol in leaves and developing seeds (Supplemental Figures 2A to 2C). It has been reported that a small portion of GAPCs in leaves could be translocated into the nucleus under stress conditions, such as cadmium and PA treatments (Kim et al, 2013;Vescovi et al, 2013). Whereas the control YFP was only present in the cytosol and nucleus as expected, no apparent accumulation of YFP-GAPC1 and YFP-GAPC2 was detected in the nucleus in either leaves or developing seeds under the conditions tested (Supplemental Figures 2A and 2C).…”

“…The contribution of GAPCs to plant function and development is complicated because they have a dual role in regulation. Several reports have linked GAPCs to the Arabidopsis response to oxidative and water stresses (Hancock et al, 2005;Holtgrefe et al, 2008;Guo et al, 2012), and two recent studies demonstrate that GAPC can move into the nucleus in plants (Kim et al, 2013;Vescovi et al, 2013). Furthermore, GAPCs have been found to interact with phosphatidic acid (PA), a lipid mediator and key intermediate in glycerolipid biosynthesis (Kim et al, 2013;McLoughlin et al, 2013).…”

Cytosolic thiol switches regulating basic cellular functions: GAPDH as an information hub?

“…Cadmium treatment induces oxidative stress and NO accumulation in roots of Arabidopsis seedlings leading to nuclear localization of GapC (Vescovi et al, 2013) (Figure 3A). GapC and thioredoxin h were previously also found to interact in the nucleus of Arabidopsis protoplasts expressing the respective FP-GapC fusion constructs (Scheibe, R., unpublished data).…”

Cytoplastic Glyceraldehyde-3-Phosphate Dehydrogenases Interact with ATG3 to Negatively Regulate Autophagy and Immunity in Nicotiana benthamiana

“…In plants, GAPDHs have been implicated in embryo development, pollen development, root growth, lipid metabolism, seed oil accumulation, and abscisic acid signal transduction (Rius et al, 2006(Rius et al, , 2008Muñoz-Bertomeu et al, 2009Kim et al, 2013;Guo et al, 2014). In Arabidopsis, cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC) is thought to function in oxidation signaling, and cadmium treatment causes inactivation of GAPC enzyme activity and relocation of GAPC from cytoplasm to nuclei (Vescovi et al, 2013). GAPC1 has been suggested to interact directly with H 2 O 2 and to be a potential modification target involved in ROS response in Arabidopsis (Hancock et al, 2005;Holtgrefe et al, 2008).…”